Selective laser melted TiB2/Ti6Al4V graded materials and first-principle calculations.

• Graded materials additive manufacturing is beneficial to fabricate TiB 2 /Ti6Al4V multi-materials successfully. • The variations of chemical composition and nanohardness were gradual along the interface. • First-principles calculations demonstrated the axis growth of TiB crystals as well as the different hardness of this system. Selective laser melting (SLM), as a rapidly developed layer-by-layer 3D printing technology, has been demonstrated that it can be used for additive manufacturing of multi-materials. In this work, TiB 2 /Ti6Al4V multi-materials were manufactured by SLM. The results showed that interfacial microstructures consisting of un-melted TiB 2 powders, columnar TiB crystals, and acicular TiB crystals were formed in the molten pool. Meanwhile, a variation nanohardness was developed with chemical compositions at the interfacial regions, owing to an in-situ reaction of Ti and TiB 2. The first-principle calculations were used to reveal the axial growth of TiB crystals as well as the different hardness of this system. [ABSTRACT FROM AUTHOR]